Missing phastsim9 

Not a huge issue, just weird.  

```
grep ^">phastsim" ./data/sequences-null/AE001825.1.phastsim-001.fasta
>phastsim0
>phastsim1
>phastsim2
>phastsim3
>phastsim4
>phastsim5
>phastsim6
>phastsim7
>phastsim8
>phastsim10
```

When I check the output files, I noticed the sequence `phastsim9` is missing. 
